The invention relates to an underbody cladding for a two-track motor vehicle having wheel-controlling links as part of a rear axle, in particular for a passenger motor vehicle, for cladding the underbody at least on one vehicle side in the region of the wheel-controlling links of the rear axle. The invention also relates to a two-track motor vehicle having such an underbody cladding, wherein the underbody cladding is designed such that, in a functional state in which it is installed on a two-track motor vehicle, it extends under the wheel-controlling links at least partially in a substantially horizontal plane, and, at least in the direction of an outer side of the vehicle, extends to close to an inner side of a rear wheel, which is connected by way of a wheel support to the wheel-controlling links, of the motor vehicle.
Generic underbody claddings of this type for two-track motor vehicles are generally known from the prior art, for example from EP 0 888 956 B1, DE 31 10 991 A, WO 2010/136460 A1, DE 10 2010 004 532 A1, DE 32 39 946 A1 and DE 102 09 591 A1. With the underbody claddings disclosed in the cited documents, it is possible, in a functional state in which the underbody claddings are installed on a two-track motor vehicle, for only a region of the underbody directly under the wheel suspension on an inner side of a wheel arch to be covered, but not adjoining regions, such that, for further coverage, it is generally the case that additional underbody cladding parts are required. This often yields aerodynamic disadvantages and, in particular, can lead to an undesired increase of the drag coefficient (cx). Alternatively, however, the described underbody claddings have relatively large-area sections of elastic form, which however tend to flutter owing to their flexible material which is required for preventing a collision with the moving wheel-controlling links.
It is therefore an object of the present invention to provide an improved, large-area underbody cladding which, in particular, exhibits a reduced tendency to flutter and extends over a larger region than just the region below the wheel-controlling links of a two-track motor vehicle.
This and other objects are achieved by way of an underbody cladding, as well as by way of a two-track motor vehicle having such an underbody cladding, in accordance with embodiments of the invention.
An underbody cladding according to the invention is characterized in that the underbody cladding is divided in the vehicle longitudinal direction into three sections, specifically into a front section, a central section and a rear section. The central section extends, at least over one region, under the wheel-controlling links on one vehicle side, and is connected at least over a part of its with to the front section and/or to the rear section. The central section is designed such that, in a functional state in which it is installed on a motor vehicle, during driving operation of the motor vehicle, the central section can at least partially follow and/or yield to a substantially vertical movement of the wheel-controlling links, wherein the front section and the rear section of the underbody cladding are designed such that they can be arranged in positionally static fashion on the motor vehicle and, in a functional state in which they are installed on the motor vehicle, cannot follow and/or yield to a substantially vertical movement of the wheel-controlling links.
A two-track motor vehicle according to the invention is characterized in that it has an underbody cladding according to the invention.
By way of an underbody cladding according to the invention, it can be achieved that, in particular during forward travel, air flow passes not directly around but passes under the wheel-controlling links of the rear axle, in particular the lower links, on the vehicle side on which the underbody cladding is arranged in a functional, installed state. That is to say, by way of the underbody cladding according to the invention under the wheel-controlling links of the rear axle, the approaching air flow can be guided past the lower wheel-controlling links in the direction of the vehicle rear end. In this way, it is possible to prevent air flow from passing in the vehicle longitudinal direction through a structural space in which the wheel-controlling links are arranged, which has a highly advantageous effect in terms of the aerodynamics and which can in particular lead to a reduced drag coefficient (cx).
The division, according to the invention, of the underbody cladding into three sections, of which the central section can yield to or deflect as a result of the movement of the wheel-controlling links and the front section and the rear section can in each case be fastened in positionally static fashion to the vehicle, makes it possible to provide an improved, large-area underbody cladding which extends over a larger region than just the region under the wheel-controlling links, and which has a reduced tendency to flutter.
Here, the positionally static arrangement relates to the attachment points of the front section and of the rear section of the underbody cladding, that is to say only these are attached in positionally static fashion or fixed in positionally static fashion, and a movement of the other regions of the front and of the rear section owing to an intrinsic movement is not thereby ruled out. In particular, the positionally static arrangement of the front section and of the rear section does not rule out a displacement or movement of parts of the front and/or of the rear section owing to the material characteristics, for example owing to an elastic material.
Here, the underbody cladding is preferably a sheetlike structure which is designed for cladding the underbody on one vehicle side or on one side of the rear axle, that is to say for cladding the wheel-controlling links of the rear axle on the right-hand side of the vehicle from below or for cladding the wheel-controlling links of the rear axle on the left-hand side of the vehicle from below. The underbody cladding is particularly preferably designed to be arranged directly under the lower wheel-controlling link or under a lower link plane which may be formed, for example, by a spring link and by a longitudinal link.
The underbody cladding may, however, also be of large-area design such that it is designed for cladding the underbody in the entire region of the rear axle, that is to say for cladding the underbody both in the region of the wheel-controlling links of the right-hand part of the rear axle and in the region of the wheel-controlling links of the left-hand part of the rear axle.
Here, the underbody cladding preferably extends, with an edge facing toward the outside of the vehicle, to as close as possible to a wheel arch, wherein the underbody cladding preferably not only extends in the direction of the outside of the vehicle to close to the inner side of the rear wheel that is connected by way of the wheel support to the wheel-controlling links, but particularly preferably also extends to close to the wheel arch in the region in front of and/or behind the rear wheel. That is to say, the underbody cladding particularly preferably extends in U-shaped or C-shaped fashion around the wheel arch, in particular at least partially in the substantially horizontal plane.
The underbody cladding is preferably designed in such a way, or extends only to so close to the wheel arch, that it can also be used in two-track motor vehicles with a rear-axle steering system, in particular in the case of motor vehicles with wheel steer angles of the rear wheels of in each case less than 5°.
In a preferred embodiment, the underbody cladding is of unipartite form, wherein the expression “unipartite” means “in one piece”. That is to say, in a particularly preferred development, the underbody cladding is not a sheetlike structure assembled from multiple individual sheetlike structures, but is a single, coherent sheetlike structure and is preferably manufactured from one piece. The unipartite form permits particularly simple assembly and inexpensive production.
In one development of the invention, the underbody cladding is divided, in such a way that the central section can at least partially follow and/or yield to a vertical movement of the wheel-controlling links, by way of at least two slots which extend toward the inside of the vehicle from an outer edge which, in a functional installed state, faces toward the inner side of the rear wheel. That is to say, it is preferably the case that a unipartite underbody cladding has at least two slots which, in each case, divide the central section from the front section and from the rear section respectively at least over a part of the width of the underbody cladding, such that the central section can, in the region of the slots or over the length of the slots, be moved in flexible fashion independently of the adjacent front section and of the adjacent rear section, in particular in such a way that adequate flexibility or yieldingness of the central section is realized, and the central section can follow a movement of the wheel-controlling links, or can be moved in yielding fashion.
The slots in this case preferably extend obliquely toward the inside of the vehicle from the rear wheel-side outer edge of the underbody cladding, wherein the slots are preferably of trapezoidal form and, in particular, form the two side edges of a trapezium. Here, it is particularly preferable for a spacing between those slot ends which are situated further toward the inside to be greater toward the center of the vehicle than the spacing between the slot ends in the region of the outer edge, that is to say the spacing of the slot ends becomes smaller toward the outside of the vehicle.
Alternatively, the slots may also be arranged so as to form the side edges of a rectangle, of a parallelogram or the like or so as to extend relative to one another in any desired manner. The underbody cladding may also have just one slot or may have more than two slots, wherein the slots may be of equal length, or else may be of different lengths. It is important merely that the slot or slots are arranged such that the central section exhibits such flexibility or yieldingness so that movement of the wheel-controlling links is not impeded or movement of the wheel-controlling links does not lead to collision or damage, in particular to the underbody cladding and/or to the wheel-controlling links.
If the underbody cladding has two slots, as described above, these preferably extend over at least two thirds of the width of the underbody cladding in the vehicle transverse direction. The slots particularly preferably have at least a length of at least one of the wheel-controlling links, wherein the two slots preferably have the same length. In some cases, it may however even be adequate for the slots to have only a length of approximately two thirds of the length of one of the wheel-controlling links.
In a particularly preferred development, in the case of two slots arranged in trapezoidal fashion, the slots are connected to one another, between their ends nearest the inside of the vehicle, by way of a film hinge, preferably by way of a film hinge running substantially in the vehicle longitudinal direction, i.e. having a hinge axis running substantially in the vehicle longitudinal direction, in a functional state in which the underbody cladding is installed on a motor vehicle.
In the context of this application, a film hinge is a hinge which is formed by a fold or the like along the hinge axis and which is formed integrally with the two elements to be connected. The film hinge, owing to its flexibility, permits a limited rotational or folding movement of the connected parts about the hinge axis.
Owing to the arrangement of a film hinge between those slot ends which are nearest the inside of the vehicle, it is possible for a type of bend line or a fold to be realized in the central section. This has the effect that that part of the central section which is nearest the outside of the vehicle can move up and down more easily between the slots, and can thus follow or yield to the movement of the wheel-controlling links more easily, in particular with less resistance. In this way, it is possible to achieve greater flexibility or greater yieldingness of the central section.
The arrangement of an additional film hinge is particularly advantageous if the flexibility or the elasticity of the material of the underbody cladding together with the slots is not sufficient to realize adequate yieldingness or an adequate resilient action of the central section in order to be able to follow or yield to a movement of the wheel-controlling links.
In an alternative embodiment, the underbody cladding is not a single-part but has a multi-part form, wherein the central section is in this case connected preferably to the front section and/or to the rear section over at least a part of the width of the underbody cladding, in particular by way of a film hinge. That is to say, in an alternative embodiment, the underbody cladding is assembled from multiple individual sheetlike structures, and preferably has a connection between the central section and the front section and/or between the central section and the rear section, which connection extends at least over a part of the width of the underbody cladding.
In a particularly preferred development, the central section is in this case connected in each case over its entire width of the underbody cladding to the front section and/or to the rear section. In this way, it is possible to realize a large-area underbody cladding by way of which flow losses in the transition regions between the central section and the adjacent sections can be substantially eliminated.
Owing to the embodiment of the connection between the central section and the front and/or the rear section as a film hinge, it is possible in a particularly simple and inexpensive manner for the central section to follow the movement of the wheel-controlling links, whereas the front and rear sections can be arranged on or fastened to the vehicle in positionally static fashion relative to the underbody, such that the front and rear sections do not need to follow or yield to the movement of the wheel-controlling links.
In a preferred development, at least one connection axis, that is to say an axis along which the central section is connected to the front section and/or to the rear section, extends through a kinematic point, projected vertically downward into the substantially horizontal plane of the underbody cladding, of at least one attachment of one of the wheel-controlling lower links to the wheel support. Here, the connecting axis runs preferably through an effective kinematic point, projected into the substantially horizontal plane, of the attachment point of a spring link and/or of a longitudinal link, in particular of the longitudinal link, to the wheel support.
If the central section is connected both to the front section and to the rear section, it is particularly preferably the case that the two connecting axes, that is to say the axis of the connection between the front and the central section and the axis of the connection between the central and the rear section, intersect in the plane of the underbody cladding in an elongation of a longitudinal axis, projected vertically downward into said plane, of one of the wheel-controlling links, in particular of the spring link. Here, the intersection point preferably lies further toward the inside, that is to say further toward the center of the vehicle, than the effective kinematic point of the attachment of the link to the vehicle body.
By way of a suitable arrangement of the connection axes, preferably by way of a suitable angular orientation of the connecting axes with respect to one another, in particular by way of the arrangement described above, it is possible, in the case of a movement of the wheel-controlling lower links, to prevent a collision with the underbody cladding, in particular with the central section, and to prevent damage to the individual components.
In a preferred embodiment, the front section and the rear section are composed of a flexible, in particular flexurally soft, material, whereas the central section at least partially has a region composed of elastic material, preferably an elastic foil, in particular a resiliently elastic foil or the like, that is to say a material that can be elastically deformed even by low forces.
In an alternative refinement, it is also possible for the front section and the rear section to have an elastic material, and for the central section to have a flexible material, wherein, in this case, too, the front section and the rear section are in each case designed such that they can be arranged in positionally static fashion on the motor vehicle.
The materials for the individual sections are in this case preferably selected or coordinated with one another such that the central section can follow or yield to or deflect as a result of the movement of the wheel-controlling links, without the wheel-controlling links colliding with the underbody cladding or individual components being damaged, and preferably without the connection between the central section and the front section and/or the rear section being damaged.
In one advantageous development, the central section is in turn divided in the vehicle longitudinal direction into at least two subsections, specifically into at least a front subsection and a central subsection, wherein the central subsection extends, at least over a region, under one of the wheel-controlling links, and preferably extends, over the region, under the link which, during functional use, performs the greatest vertical movement. The central subsection is particularly preferably connected at least over a part of its width to the front subsection. That is to say, in a preferred embodiment, the underbody cladding is divided into at least four sections overall: a front section, a front subsection, a central subsection and a rear section, wherein the two subsections form the central section, and wherein the central subsection is particularly preferably at least partially connected to the front subsection.
In a particularly preferred development, the central section is however divided in the vehicle longitudinal direction into at least three subsections, specifically into at least a front subsection, a central subsection and a rear subsection, wherein the central subsection likewise extends, at least over a region, under one of wheel-controlling links, and preferably extends, over the region, under the link which performs the greatest vertical movement during functional use. The central subsection is preferably connected at least over a part of its width to the front subsection and/or to the rear subsection. That is to say, in a particularly preferred embodiment, the underbody cladding is divided into at least five sections overall: a front section, a front subsection, a central subsection, a rear subsection and a rear section, wherein, in this case, the three subsections form the central section, and the central subsection is preferably connected to the front subsection and/or to the rear subsection.
If the subsections are not connected to one another, it is advantageous, in particular with regard to the aerodynamic characteristics of the underbody cladding, for the subsections to extend as close as possible to one another, that is to say, when the subsections are in a functional state in which they are installed on a motor vehicle, for only a narrow, that is to say extremely small, gap to be provided between them, through which as far as possible no air flow can pass from an underside of the underbody cladding through to a top side of the underbody cladding.
It is preferable for only the central subsection to have, or be composed of, elastic material, whereas the front subsection and the rear subsection are composed of flexible material, in particular from the same flexible material as the front section and the rear section. It is particularly preferable in each case for the front subsection to be connected integrally to the front section and for the rear subsection to be connected to the rear section by way of a film hinge.
The central subsection is preferably composed of elastic material and connected preferably to the front subsection and/or to the rear subsection, that is to say to the immediately adjoining subsections, by way of a welt connection.
Below, a welt connection is to be understood to mean a connection which is formed by way of the positively locking engagement of a welt into a welt rail, wherein here, a welt refers to an edge thickening of a flexible or elastic sheetlike structure. The welt can be inserted into the welt rail such that, perpendicular to the welt rail axis, a positively locking connection is formed between welt rail and welt, such that the sheetlike structure can be areally tensioned transversely with respect to the welt rail. Welt connections are generally known per se from the prior art, for example for the fastening of an awning to a caravan.
An underbody cladding in the case of which the front subsection and the central subsection are connected to one another by way of a welt connection over the entire width of the underbody cladding, but the rear subsection is separated from the central subsection merely by way of a gap, in particular an extremely narrow gap, with regard to a rest position of the wheel-controlling links, has proven to be advantageous in particular with regard to costs. That is to say, an underbody cladding in the case of which the central subsection is connected only to the front subsection, but not to the rear subsection, but rather is separated therefrom by a gap, is particularly advantageous with regard to costs.
To prevent fluttering, the underbody cladding is, in a functional state in which it is installed on a motor vehicle, preferably fastened at least by way of one section, preferably by way of the central section, in particular by way of the central subsection, at least regionally to one of the wheel-controlling links. Said section is in this case particularly preferably attached to the link which, during functional use of the motor vehicle, can assume an absolutely lowest position in a vertical direction, in particular to the spring link.
For the fastening of elastic sections, or of sections which are not inherently sufficiently stiff, it is possible for so-called inlays to be inserted as fastening device into the underbody cladding, which inlays permit fixing or attachment of the respective section to the wheel-controlling links.
In regions in which the underbody cladding is inherently sufficiently stiff, the fastening is preferably realized by way of at least one Cardan bearing, which permits relative movements in all directions and simultaneously permits angular compensation. A particular advantage of Cardan bearings is that the stiffness thereof is generally substantially adjustable according to load direction.
The underbody cladding is particularly preferably designed in such a way, and/or can be fastened to the motor vehicle in such a way, that, in particular, during spring compression movements of the rear wheel, the central section remains in its previous position and, during spring extension movements of the rear wheel, the central section can follow the movement of the wheel-controlling links. For this purpose, it is preferably the case that the central section can, during spring compression movements, be decoupled from the wheel-controlling links, in particular by way of a correspondingly designed connection between the central section and the wheel-controlling links. This permits, in particular in the case of high load states of the motor vehicle, optimum functionality of an underbody cladding according to the invention, in particular with regard to aerodynamics.
The fastening of the underbody cladding elsewhere, that is to say the fastening to the motor vehicle elsewhere, is preferably realized in a conventional manner such as is known from the prior art, for example by way of clips, metal clamps, screws or the like.
In a preferred embodiment, the underbody cladding has at least one flow lip, preferably in the central section, in particular parallel to the inner side of the rear wheel, that is to say in the vehicle longitudinal direction, on the outer edge of the underbody cladding. Here, the flow lip preferably extends over the entire length of the central section in the vehicle longitudinal direction, that is to say over the entire region of the central section. The flow lip may however also be longer, and may extend into the front section and/or the rear section, or else may run all the way along that outer edge of the underbody cladding which faces toward the rear wheel, or else may be shorter, in accordance with requirements.
The flow lip is preferably a flow lip which extends substantially vertically upward, that is to say from the underbody cladding toward the links, or an upwardly curved flow lip, a flow strip or the like. In some cases, it may however also be advantageous for the flow lip to extend downward, or to extend both upward and downward.
In some cases, it may furthermore be advantageous for a flow lip to be arranged in the transition region between the individual sections, in particular if the sections are not connected to one another but are separated by a gap, in particular between the rear section and the central section. In this ways, it is possible to prevent a part of the air flow from being conducted between the individual sections through to the top side of the underbody cladding.
It is also possible for multiple flow lips to be provided, preferably for flow lips to be provided both along that outer edge of the underbody cladding which faces toward the rear wheel and in the region of the division of the individual sections.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.